It is known to perform gel electrophoresis for the study of proteins and protein mixtures from biological material. Proteins are separated according to their isoelectric points by isoelectric focusing, or they are separated according to molecular weight by sodium dodecyl sulfate gel electrophoresis. A combination of these two unidimensional techniques makes it possible to perform gel electrophoresis in two dimensions. This bidimensional gel electrophoresis as conventionally practiced requires a great expenditure of time, amounting to as much as two days. It also requires a high consumption of expensive reagents, such as, for example, ampholytes; furthermore, complex and expensive apparatus are required, and still furthermore a relatively large amount of sample substance is required for the performance of gel electrophoreses.
By the invention, a method and an apparatus of the kind mentioned in the beginning is to be developed, whereby the amount of time, material, apparatus and sample substance, and hence the effective cost of the performance of gel electrophoresis, will be reduced to a minimum.